This invention relates to a device for heating water in a coffee machine between a pump and an extraction system.
It is known that espresso coffees can be prepared by injecting hot water under pressure either onto a bed of roasted and packed ground coffee or into a closed cartridge already containing the dose of roasted and ground coffee, for example of the type described in Swiss Patent No. 605 293. On the hand, European Patent application No. 87107012, now European Patent No. 250,810, states steps are required to obtain a good espresso coffee, namely: a first step in which the coffee is prewetted, an aeration step and the actual extraction step. The present invention relates to a device for carrying out the above-mentioned process to obtain good aeration of the extracted coffee using a mixture of the extraction water with the air trapped in the heating element.